Macromolecule concentration

Eigute 31 also shows that the point at which the gel layer forms and the flux teaches a maximum depends on the concentration of the macromolecule in the solution. The mote concentrated the solution, the lower the flux at which the gel layer forms. The exact relationship between the maximum flux and macromolecule concentration can be obtained from equation 2, expressing the concentration at the membrane surface, as at which point /becomes giving equation 3. 

Consequently, any association must decrease chain tendency to degradation. However, the existence of such intermediate particles at association, which possess lower height of the reaction barrier, may be probable. In this case, kinetic probabilities of the process performance increase. A sufficiently sharp increase of kinetic probabilities of the reaction must be observed in the case, if a low-molecular compound (oxygen, for example) participating in the reaction is highly stressed. But it is necessary to remember that even if kinetic probabilities of the process are increased, the reaction will also proceed in the case of its thermodynamic benefit. As association depends on macromolecule concentration, it should be taken into account at the calculation of kinetic and thermodynamic parameters of the process according to thermodynamics. 

Generally, the activity coefficient y depends on the composition of solution. In the ranges of our narrow purposes of investigations of the macromolecules chemical potential conformation term influence on the osmotic pressure of polymeric solutions we will be neglect by the change of y lying y = const in all range of the macromolecules concentrations into solution. This permits to write... 

Although we shall carry along the term in Equation (21.28) for the variation of In 7, with c,—for in practice the macromolecule concentration may cover a wide range from meniscus to bottom of the cell (Fig. 21.2)—we shall assume that the change in In 7, of the macromolecule with change in concentration of other solutes in the solution is negligible to a good approximation. Within these specifications. Equation (21.24) can be reduced to... 

Finally, for biological molecules that are macromolecules, such as most proteins, Eq. (4.23) can also be used to relate the relative viscosity to the intrinsic viscosity of the solution and the macromolecule concentration ... 

The initiation rate is proportional to the concentration of macroradicals and of the macromolecules. In view of this, the initial scission reactions may proceed fairly intensively even with low macroradicals concentration, as the macromolecules concentration is high. As a result of the initiating scission, block copolymers are formed and new macroradicals are created which continue this chain process further. 

The crystallization of a biological macromolecule is realized by manipulation of one or more chemical and thermodynamic variables, such that the solubility of a target molecule in a concentrated solution is reduced, thereby promoting a transition to the solid phase in the form of a well-ordered crystal. In principle, any thermodynamic variable that may directly, or indirectly, affect protein solubility may be used to induce crystallization. Variables that are most often manipulated include macromolecule concentration, ionic strength, identity and concentration of precipitating agents, pH, temperature and small-molecule additives. Together, these variables comprise a vast multi-dimensional chemical phase space that must be systematically explored to discover crystallization conditions. 

Commonly, the sample produced for heteionuclear triple-resonance 3-D NMR experiments must be ImM or greater in macromolecule concentration in approximately 400-600uL of solution in a SmM NMR tube. However, it should be noted that there are efforts underway in several laboratories aimed at developing probes which can accommodate larger sample volumes. The solution used is routinely 90% H2O with 10% D2O added for field locking. The sample should be free of impurities, especially other proteins which may copurify and may also be labeled with and N isotopes. 

The large number of variables involved in complex coacervation (pH, ionic strength, macromolecule concentration, macromolecule ratio, and macromolecular weight) affect microcapsule production, resulting in a large number of controllable parameters. These can be manipulated to produce microcapsules with specific properties. Complex coacervate microcapsules have been formulated as suspensions or gels, and have been compounded within suppositories and tablets.[ l... 

Once conditions for nucleation and growth have been identified and the investigation of variables more or less complete, the concentration of the protein should be gradually reduced in increments to moderate the growth of the crystals. As a rule, the largest and most perfect crystals result when the rate of incorporation of molecules is slow and orderly. Reduction of macromolecule concentration is an effective means for controlling this. 

Finally, the viscosity of the samples may be important if macromolecule concentrations are high enough to contribute to band broadening as a result of unstable flow. 

The second reason is owed to the chromophore itself. At high concentrations, aggregation could occur. In this case, we are going to have two values of c, corresponding to low and high concentrations. Plotting the optical density as a function of the macromolecule concentration will yield two plots with two different values of c. 

Figure 1. Electrophoretic mobility of calcium oxalate monohydrate vs macromolecule concentration. The numbers near the data points are the corresponding solution pH values.

It is often convenient to perform experiments with constant ligand and varying macromolecule concentration. In this case Cm. and hence Sjot, are the variables and Itot is fixed. Rather than equations 40 and 41 we then use ... 

In this case, the signal monitors the progress of the saturation of a macromolecule and a normal titration (addition of a ligand to a constant macromolecule concentration) is generally performed. Any physico-chemical intensive property of the macromolecule (e.g. fluorescence intensity, fluorescence anisotropy, absorbance, circular dichroism, viscosity, etc.) can be used to monitor the binding, if this property is affected by the state of ligation of the macromolecule. 

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